The total (budget) variance is given by the equation}

a. \((A P \times A Q)-(S P \times S Q) P\).

b. \((S P \times A Q)-(A P \times S Q) P\).

c. \((S P \times A Q)-(S P \times S Q) P\).

d. \((A P \times S P)-(A Q \times \widetilde{S Q}) P\).

e. None of the above.